fix(API): adapt to changed yup-oauth2 API

The latter changed a lot, to the better, and we handle the new
return types accordingly.

Related to #74

src/mako/api/lib/mbuild.mako

@@ -665,16 +665,20 @@ else {
 
         loop {
             % if default_scope:
-            let mut token = ${auth_call}.token(self.${api.properties.scopes}.keys());
-            if token.is_none() {
-                token = dlg.token();
-            }
-            if token.is_none() {
-                ${delegate_finish}(false);
-                return Err(Error::MissingToken)
-            }
+            let token = match ${auth_call}.token(self.${api.properties.scopes}.keys()) {
+                Ok(token) => token,
+                Err(err) => {
+                    match  dlg.token(&*err) {
+                        Some(token) => token,
+                        None => {
+                            ${delegate_finish}(false);
+                            return Err(Error::MissingToken(err))
+                        }
+                    }
+                }
+            };
             let auth_header = Authorization(oauth2::Scheme { token_type: oauth2::TokenType::Bearer,
-                                                             access_token: token.unwrap().access_token });
+                                                             access_token: token.access_token });
             % endif
             % if request_value:
             request_value_reader.seek(io::SeekFrom::Start(0)).unwrap();

src/rust/api/cmn.rs

@@ -125,9 +125,12 @@ pub trait Delegate {
     }
 
     /// Called whenever the Authenticator didn't yield a token. The delegate
-    /// may attempt to provide one, or just take is a general information about the
-    /// pending impending failure
-    fn token(&mut self) -> Option<oauth2::Token> {
+    /// may attempt to provide one, or just take it as a general information about the
+    /// impending failure.
+    /// The given Error provides information about why the token couldn't be acquired in the
+    /// first place
+    fn token(&mut self, err: &error::Error) -> Option<oauth2::Token> {
+        let _ = err;
         None
     }
 
@@ -230,7 +233,7 @@ pub enum Error {
     MissingAPIKey,
 
     /// We required a Token, but didn't get one from the Authenticator
-    MissingToken,
+    MissingToken(Box<error::Error>),
 
     /// The delgate instructed to cancel the operation
     Cancelled,
@@ -258,8 +261,8 @@ impl Display for Error {
                 writeln!(f, "The application's API key was not found in the configuration").ok();
                 writeln!(f, "It is used as there are no Scopes defined for this method.")
             },
-            Error::MissingToken =>
-                writeln!(f, "Didn't obtain authentication token from authenticator"),
+            Error::MissingToken(ref err) =>
+                writeln!(f, "Token retrieval failed with error: {}", err),
             Error::Cancelled => 
                 writeln!(f, "Operation cancelled by delegate"),
             Error::FieldClash(field) =>

src/rust/cli/cmn.rs

@@ -169,25 +169,38 @@ impl JsonTokenStorage {
 }
 
 impl TokenStorage for JsonTokenStorage {
+    type Error = io::Error;
+
     // NOTE: logging might be interesting, currently we swallow all errors
-    fn set(&mut self, scope_hash: u64, token: Option<Token>) {
+    fn set(&mut self, scope_hash: u64, _: &Vec<&str>, token: Option<Token>) -> Option<io::Error> {
         let json_token = json::encode(&token).unwrap();
-        let res = fs::OpenOptions::new().create(true).write(true).open(&self.path(scope_hash));
-        if let Ok(mut f) = res {
-            f.write(json_token.as_bytes()).ok();
+        match fs::OpenOptions::new().create(true).write(true).open(&self.path(scope_hash)) {
+            Ok(mut f) => {
+                match f.write(json_token.as_bytes()) {
+                    Ok(_) => None,
+                    Err(io_err) => Some(io_err),
+                }
+            },
+            Err(io_err) => Some(io_err)
         }
     }
 
-    fn get(&self, scope_hash: u64) -> Option<Token> {
-        if let Ok(mut f) = fs::File::open(&self.path(scope_hash)) {
-            let mut json_string = String::new();
-            if let Ok(_) = f.read_to_string(&mut json_string) {
-                if let Ok(token) = json::decode::<Token>(&json_string) {
-                    return Some(token)
+    fn get(&self, scope_hash: u64, _: &Vec<&str>) -> Result<Option<Token>, io::Error> {
+        match fs::File::open(&self.path(scope_hash)) {
+            Ok(mut f) => {
+                let mut json_string = String::new();
+                match f.read_to_string(&mut json_string) {
+                    Ok(_) => Ok(Some(json::decode::<Token>(&json_string).unwrap())),
+                    Err(io_err) => Err(io_err),
+                }
+            },
+            Err(io_err) => {
+                match io_err.kind() {
+                    io::ErrorKind::NotFound => Ok(None),
+                    _ => Err(io_err)
                 }
             }
         }
-        None
     }
 }